PCV System - Diesel: Maintenance: Notes
An engine may idle slow or rough due to a clogged PCV valve or system. Never adjust idle speeds without first checking entire PCV system. Check for cracked or plugged hoses.
Remove PCV valve cover and check for deterioration or damage to diaphragm. Check diaphragm for breakage. See Figure . Check PCV valve body for contamination. Check baffle plate, located inside valve cover, for contamination and plugging.
CAUTION:
If a PCV system component becomes clogged, all crankcase ventilation will stop and serious engine damage could occur.
Although following manufacturer's service procedures is recommended, PCV system should be serviced more frequently if vehicle is operated under severe conditions (extreme dust, prolonged idling, trailer hauling or short trips in cold weather).